ORGN 91 |
| Tetrathiatriarylmethyl (TAM) radicals are commonly used as oximetry probes for electron paramagnetic resonance imaging (EPRI) applications. three esters and one carboxylate salt as trityl radicals were synthesized. The stability of the radicals in the presence of molecular oxygen and biological milieu were experimentally assessed using EPR spectroscopy. A potential mechanism for decay of the trityl radicals was proposed based on the literature results, EPR spectroscopic and mass spectrometric studies, and suggests that this degradation process involves an arylperoxy radical which can further decompose to alcohol or quinone products. The electronic properties and the thermodynamics for molecular oxygen addition to these trityl-type radicals with varying degrees of substitution and varying substituents were theoretically investigated. This study demonstrates how computational chemistry can be used as a tool to assess radical stability in complex systems and aid in the future design of more biostable trityl radicals. |
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Physical Organic Chemistry: Calculations, Mechanisms, Photochemistry, and High-Energy Species
1:00 PM-5:20 PM, Sunday, 10 September 2006 Moscone Center -- Room 133, Oral
Division of Organic Chemistry |